放牧对滩涂底栖动物的影响

于2005年5月（春季）和10月（秋季），调查了放牧对上海市崇明东滩大型底栖动物的影响.调查采样设置3个样区，其中Ⅰ、Ⅱ样区在放牧区，Ⅲ样区在非放牧区，3个样区均在潮间带的中潮带，共计90个样方.采集到底栖动物13种，其中节肢动物7种，软体动物4种，环节动物2种.Ⅰ、Ⅱ和Ⅲ样区春季分别有6、8和10种，秋季6、8和12种.各样区秋季底栖动物的平均密度均高于春季，春、秋季各样区的平均密度又均以Ⅲ样区最高.生物量与密度变化大体相似，以Ⅲ样区最高.与Ⅰ、Ⅱ样区相比，Ⅲ样区的多样性指数、均匀度和丰富度均最高，说明放牧改变了底栖动物种类分布的格局，使底栖动物的密度、生物量均有不同程度的改变，且放牧对崇明东滩底栖动物的生物多样性产生了一定的负面影响.

Effects of grazing on zoobenthos community in beach.

In May (spring) and October (autumn) 2005, the effects of grazing on the zoobenthos community in Chongming Dongtan wetland of Shanghai were investigated. A total of 3 transects including 90 sampling plots were set up. Transects Ⅰ and Ⅱ were in feeding area, and transect Ⅲ was in non-pasture area. All of these three transects were set in mid-tidal zone. 13 zoobenthos species were observed, with 7 species of arthropod, 4 species of mollusk, and 2 species of annelid. In spring, there were 6, 8 and 10 species in transects Ⅰ, Ⅱ and Ⅲ, while in autumn, the species number was 6, 8 and 12, respectively. The mean abundance of zoobenthos community in all transects was higher in autumn than in spring, and transect Ⅲ had the highest mean abundance and biomass both in autumn and spring. Transect Ⅲ also had the highest evenness, richness and diversity, indicating that grazing could change the species distribution of zoobenthos, and affect their abundance and biomass to different degree.Grazing had made certain negative effects on the biodiversity of zoobenthos community in Chongming Dongtan wetland.